Phase II, single-arm, open-label single center study that assess clinical feasibility and safety of 3 cycles neoadjuvant Sintilimab plus chemotherapy in EGFR-mutant stage IIB-IIIB NSCLC (excluding N3) followed by optional adjuvant treatment upon investigators' decisions.

35 eligible patients will be enrolled and 3 cycles of Sintilimab 200mg + doublet platinum-based chemotherapy will be administered. Dynamic blood samples before, during or after neoadjuvant treatment will be obtained for exploratory analysis. Patients who showed inferior response to neoadjuvant treatment leading to unresectable disease will be scheduled for local radiation or other potential subsequent treatment regarding multidisciplinary discussion. After completion of local treatment (surgery or radiation), patients will be provided with optional adjuvant treatment including EGFR-TKI upon investigators' consideration. Patients will be followed with 5 years after surgery. The primary objective of the study is major pathological response (MPR) defined as no more than 10% residual tumor found in primary lung cancer.

Inclusion Criteria:

1. Age :18 Years to 75 Years;
2. ECOG physical score 0-1 points; expected survival time ≥ 3 months;
3. Pathologically confirmed diagnosis with Stage II-IIIB(N2) NSCLC which harbored sensitive and rare EGFR alteration. Suspected N2 disease should be confirmed by either mediastinoscopy or EBUS. N1 disease could be determined through PET/CT but biopsy of primary lung cancer is needed;
4. At least one measurable target lesion according to the RECIST 1.1 standard;
5. The main organ function meets the following criteria: 1) blood routine: absolute value of neutrophils ≥ 1.5 × 109 / L, platelets ≥ 75 × 109 / L, hemoglobin ≥ 80 g / L; 2) blood biochemistry: total bilirubin ≤ 1.5 times the upper limit of normal value, aspartate aminotransferase and alanine aminotransferase ≤ 2.5 times the upper limit of normal value (if liver metastasis, ≤ upper limit of normal value 5 times), serum creatinine ≤ 1.5 times the upper limit of normal;
6. Subjects voluntarily joined the study and signed informed consent, with good compliance to follow-up.

Exclusion Criteria:

1. Stage I and stage IV NSCLC;
2. Large panel NGS indicated ALK fusion or any other driver mutations;
3. Histologically confirmed small cell lung cancer (including lung cancer mixed with small cell lung cancer and non-small cell lung cancer);
4. Patients who have previously used any other anti-tumor drugs or radiotherapy;
5. A history of active bleeding within the 6 months before enrollment, or receiving thrombolysis or anticoagulant therapy, or the investigator believes that there is a clear tendency to gastrointestinal bleeding (such as esophageal varices with bleeding risk, local activity) Ulcer lesions, etc.) or active hemoptysis;
6. Patients with any underlying disease that investigators consider it may affect patient's prognosis including sever cardiovascular, pulmonary disease or serious infections;
7. Clinically obvious gastrointestinal abnormalities, which may affect the intake, transport or absorption of drugs (such as inability to swallow, chronic diarrhea, intestinal obstruction, etc.), or patients with total gastrectomy;
8. Pregnant or lactating women; those who have fertility are unwilling or unable to take effective contraceptive measures;
9. Patients with low compliance or willingness to take the drugs and surveillance.

After the primary data including translational analysis has been published, IPD of detailed clinical information and comics data could be available from principle investigator upon reasonable request.

After the primary data including translational analysis has been published, IPD of detailed clinical information and comics data could be available. Approximate 48 months after initiation of enrollment.

IPD could be accessed from principle investigator upon reasonable request.